To soothe the public opinion, Rossiu overthrows Simon and puts him under arrest. But when the Anti-Spirals launch a large-scale attack on Kamina City, he is left with no option but to let Simon engage the enemy using the Gurren-Lagann, not before resorting to extremes to put him under his control.

After the Anti-Spirals' first attack and Nia's astonishing announcement, Simon looks desperately for her, while Rossiu finally completes his secret project.

During the following seven years, a new civilization rises and prospers under Simon's leadership. However, these peaceful times come to end when the threat mentioned in Lordgenome's last words starts to reveal itself.

A recap of the story's events from the previous episodes.

The last of the Divine Generals fall, and the city of Teppelin collapses, revealing a Gunman of gigantic proportions. Simon and Nia struggle to pass through it in order to confront her father, the Spiral King himself.

At last, Team Dai-Gurren arrives at the outskirts of Teppelin, but before aiming to the city, they must face a combined full-scale attack of Cytomander and Guame's forces.

Trying to do her part in Team Dai-Gurren, Nia decides to become a cook, but just before the crew have a taste of her dishes, Cytomander, the fourth member of the Divine Generals, launches an aerial attack on the Dai-Gurren. Simon leads the counter-attack on the Gurren-Lagann, this time accompanied by Yoko, who replaces a sick Rossiu.

Team Dai-Gurren are now on their way to Beastmen's capital city, Teppelin but there's a vast ocean in their way. The only way for them to get across is for the Dai-Gurren to be modified, so while they wait everyone goes to chill out at the beach. Once preparations are complete, the Great Gurren Brigade begins their cruise, but there's an ambush waiting for them.

Team Dai-Gurren falls into a trap set by the third member of the Four Divine Generals, Guame. The Team is taken captive and stored underground to await execution. While digging an escape path, Simon finally understands Kamina's last words to him and after having a discussion with Guame, Nia finds out the reason why she was thrown away.

Nia true identity is revealed, as she flaunts her authority to get rid of another one of the Four Divine Generals, Adiane. The members of the Great Gurren Brigade are now suspicious of Nia and her true intentions, but she is only concerned about the depressed Simon. Adiane later returns to finish them all off, with Lordgenome's blessing.

Team Dai-Gurren managed to take control of the enemy fortress, but is still mourning the death of one of their own, especially Simon. After falling off a cliff, he notices a Gunman throw a capsule into a deep valley. Simon inspects it and finds he is able to open it with the same drill key he uses to pilot Lagann, and inside is a young human girl named Nia, but their introduction is cut short when an enemy Gunman appears.

Having temporarily stalled Viral and Thymilph in the last skirmish, the Team Gurren and their newly arrived allies join forces as "Team Dai-Gurren" and launch a decisive strike against the regrouping Gunmen force.

Thymilph, one of the Four Divine Generals of the mysterious Spiral King, arrives to support Viral's Enki, with the massive mobile Gunmen fortress, the Dai-Ganzan. Kamina and Simon pilot the Gurren-Lagann against seemingly overwhelming odds.

Continuing to the Gunmen rallying point, Team Gurren finds themselves on a strange hot springs getaway.

Team Gurren must find their way out of a strange underground village where Gunmen are worshipped as divine beings.

Team Gurren must work together with the eccentric Black Syblings to take down a Beastman foe on empty stomachs.

Kamina and Simon must work together to defeat a dangerous new Beastman threat.

Now that they've made it to the surface, Simon and Kamina must join together with Yoko and her village to defeat the Beastmen pursuing them.

Living underground in Giha Village, Simon and Kamina dream of a life on the surface. When their home is invaded from above, it is up to them to activate the mysterious mecha Lagann and save their village.